The present invention is directed to pocket door cabinets and, more particularly, to an improved door suspension system which insures that the slide brackets move smoothly and do not bind.
Pocket door systems have become increasingly popular in recent years. In such systems, one or two doors are used to cover the front opening of a cabinet, such as an entertainment center. Each door is hingedly mounted at the top and bottom of the side edge thereof to a slide bracket which is mounted on a pair of parallel horizontal tracks affixed to the inner side wall of the cabinet. After the door(s) swings open from a closed position, it is then slid along the tracks into retracted parallel relationship with the adjacent side wall. While the cabinet door or doors are generally opened by pivoting about a vertical axis along the outside edge, on some occasions (bookcases with flipper-type doors) the cabinet door may open by pivoting about a horizontal axis.
In such pocket door systems, it is important that the sliding fittings which connect the top and bottom of the door to the slide tracks operate smoothly without binding. Binding is sometimes caused by the weight of the door pulling forwardly on the upper fitting moving it out of vertical alignment with the lower fitting. Conversely, a force exerted against the upper portion of the door, as when moving it rearwardly, can also cause the upper fitting to move rearwardly further than the lower fitting, thus creating a misalignment situation.
Various approaches to resolving the aforesaid problem have appeared in the prior art. Some manufacturers rigidly connect the upper and lower fittings by a vertical wooden or metal plate which prevents skewing of the fittings. Another approach utilizes a vertical rod connecting the upper and lower fittings, which rod has a pinion at each end thereof operatively fitting into a rack extending along the top and bottom of the inner wall. The cooperation between the vertical rod and the rack and pinion assemblies thereby prevent misalignment and binding of the slide assemblies. In a third approach, the door is hinged on a scissor-pantograph type hinge and simply slides along a path parallel to the end wall without binding. While the above mechanisms are apparently reliable and seem to adequately solve the skewing problem in such types of doors, they are very expensive, and therefore are generally used only in more expensive furniture.
A less expensive approach is to connect the upper and lower hinge plates by means of a cable which extends over a plurality of pulleys to transmit the force tending to skew the bottom hinge to the top hinge. One example of this approach is shown in the German Patent No. 1,143,415 to Ziehl and the U.S. Pat. No. 4,729,612 to Stone. Both of these arrangements are substantially similar to each other and provide a cable with the ends thereof affixed to the top and bottom hinge plates. The cable extends in a Z path from the upper hinge plate across a pulley at the rear end of the top slide and down across another pulley at the front end of the bottom slide and back to the bottom hinge plate.
A second example of such a cabling arrangement is shown in U.S. Pat. No. 4,974,912 to Rask et al. In this approach, two cables are provided, each attached at one end to the back end of one fixed slide member and at the other end to the front end of the other fixed slide member. Each cable is slidably attached to the movable members of the slide assemblies such that the pair of cables trace an "I" figure. The pair of cables in this arrangement effectively prevent the movable members of the slide assemblies from moving out of a predetermined relationship to each other.
In the present invention, yet another approach is provided whereby equilibrium of the pocket door system is established and maintained. Thus the present approach is a pre-balanced system in which the weight of the door does not change the equilibrium. Only fine adjustments are necessary to allow for door, cabinet, and gap variations. While extremely effective, the system of the present invention is extremely simple, has minimized the number of parts, and facilitates assembly and service.
In the present suspension system, two cables are utilized, one of which extends rearwardly from the upper bracket across an upper rear pulley, downwardly and forwardly around a lower front pulley and back into the lower bracket. A second cable follows the opposite path from the upper bracket forwardly around an upper front pulley, downwardly and rearwardly around a lower rear pulley, and forwardly into the lower bracket. Both cables are of equal length and substantially inelastic.
By having two cables, skew from both downward and upward forces are prevented. Parallel movement of the slide brackets is maintained. This occurs because the two cable arrangement insures tension on the cable arrangement regardless of whether the skewing component force is downward or upward. In either case, the brackets remain one atop the other.
Further improvements in the present invention include the assembly of the front and rear pulleys onto the drawer slides themselves at predetermined engineered locations, rather than being separately attached to the side walls. This makes the slide assemblies easier and faster to assemble and mount and thus less expensive. Further, the pre-assembly of the pulleys to the slide brackets insures proper positioning of the components. The only thing necessary for the installer to do is to insure that the slides are parallel, then everything functions correctly.
A second feature of the present invention is the provision of an adjustment device mounted on each slide bracket by which the length of each cable may be adjusted by a simple screw device. The bracket and screw arrangement is so positioned that the screw head faces the front of the cabinet. Thus the adjustment screw is accessible from the front direction when the door is open which considerably facilitates adjustment.
In general, the present invention is directed to a pocket door suspension system for hingedly mounting a pocket type cabinet door for pivotal movement between a closed position in which the door is perpendicular to a cabinet side wall and an open position in which the door is parallel to and alongside the cabinet side wall. In the open position, the door is adapted for sliding movement relative to the side wall. The suspension system includes an upper and lower slide track assembly mounted to the cabinet side wall in parallel spaced arrangement to each other. A slide bracket is attached to each slide track assembly for movement therealong. Each of the slide brackets are hingedly connected to the edge of the cabinet door. The suspension system is, in reality, an alignment mechanism for maintaining the slide brackets in vertically aligned relationship. Toward this end, the suspension system includes a first and second cable and a plurality of pulleys. One of the pulleys is mounted adjacent each of the front and rear ends of the upper and lower slide track assemblies. The first cable is connected to the upper slide bracket and extends rearwardly therefrom over the pulley at the rear end of the upper slide track assembly, downwardly to and over the pulley at the front end of the lower slide track assembly and rearwardly back to the lower slide bracket. The second cable is connected to the upper slide bracket and extends forwardly therefrom over the pulley at the front end of the upper slide track assembly, downwardly to and over the pulley at the rear end of the lower slide track assembly, then forwardly to the lower slide bracket.
The aforesaid cables are movable with the slide brackets during sliding movement between the open and closed positions of the door and maintain the vertical alignment of the slide brackets regardless of whether an upward or downward force is exerted on the door.
The cables are substantially inelastic and of the same effective length. In a preferred embodiment, the suspension system includes an adjustment mechanism associated with each of the cables for adjusting the effective length thereof. Preferably the adjustment mechanism is accessed from the front of the cabinet.
It is therefore an object of the present invention to provide a suspension system for pocket doors which insures that the slide brackets move smoothly and do not bind.
It is a further object of the present invention to provide a suspension system of the type described which is inexpensive and which is more easily assembled and installed within the cabinet.
A further object of the present invention is to provide a suspension system of the type described which maintains vertical alignment of the slide brackets regardless of whether the force on the corresponding door is upward or downward.
Yet a further object of the present invention is to provide a pocket door suspension system in which equilibrium is established and maintained without regard to the weight of the door or the force applied against it.